Nikita Zadorov was born on April 16, 1995 in Moscow, Russia. A top prospect in his Russia, he joined the London Knights of the Ontario Hockey League for the 2012-13 season. In 63 games for the Knights, the towering defender recorded six goals and 19 assists. The following summer he was selected 16th overall in the NHL Entry Draft by the Buffalo Sabres.

Zadorov would begin the 2013-14 season at the NHL level. He would appear in seven games for the Sabres before being returned to the Knights of the OHL. With the Knights Zadorov would should progress at both ends of the ice. In 36 games he scored 11 times and added 19 assists for 30 points.

The 2014-15 season would be Zadorov's first full NHL campaign. He would suit up for 60 games for the Sabres, registering three goals and 12 assists.

On June 26, 2015, Zadorov was traded along with Mikhail Grigorenko, J.T. Compher, and a second round draft pick to the Colorado Avalanche for Ryan O'Rielly. Zadorov would split time during the 2015-16 season between the Avalanche and the club's AHL affiliate, the San Antonio Rampage. In 22 games for the Avalanche, he recorded a pair of assists and in 52 games for the Rampage, the big defenceman scored 10 times and added 19 assists.